1. Field of the Invention
This invention is in the field of electrical connectors for use with x-ray emitting tubes, particularly of the rotating anode type.
2. Description of the Prior Art
Referring to FIGS. 1-3, a typical prior art cable termination system for x-ray tubes is shown. FIG. 1 shows the outline of a prior art x-ray tube enclosure 10 which is typically a lead-lined casting made up generally of three intersecting cylinders. The main cylinder portion 12 typically carries a prior art tube insert in a glass envelope 26 containing a rotating anode. Enclosure 10 further has a collimator mounting surface 14 formed as an integral part thereof. Intersecting minor cylinder portions 16a,b (positioned as shown to block unwanted x-ray emissions) are the part of the enclosure 10 which provides a housing for prior art cable termination receptacles, shown in more detail in FIG. 2, a view along section 2--2' of FIG. 1.
FIG. 2 shows a prior art female receptacle 18 (shown in halfsection view) mounted in cylinder portion 16b of enclosure 10 by means of a locking ring 20. Ring 20 forces flange 22 against a sealing washer 24, to maintain liquid-tight integrity of enclosure 10, which is typically completely oil filled to provide for enhanced electrical insulation and thermal conduction between envelope 26 and enclosure 10. Female receptacle 18 has one or more electrical terminal assemblies or sockets 28 sealed against fluid leakage. FIG. 2 shows one terminal assembly 28 connected to a wire and lug assembly 30 having a number of layers of insulation. Assembly 30 is shown connecting receptacle 18 of cylinder portion 16b to the anode terminal 32 of envelope 26. An electrical insulating boot 34 is provided over the terminal end of receptacle 18 to provide additional electrical insulation.
Cylinder portion 16a typically contains an identical receptacle 18 whose terminal assemblies 28 are used to connect to the cathode connections of glass tube envelope 26.
The cable side of such prior art termination systems is shown in FIGS. 3a and b. An insulating plug 36 carries electrically conductive terminals 38 adapted to be received in sockets or terminal assemblies 28. Proper orientation of plug 36 in receptable 18 is provided by key 40 and keyway 42. One or more terminals 38 is connected by means of a bare copper wire 44 through a splice connector 46 to a conductor contained within cable 48 after additional insulation 50 is added to the conductor. Although two connections are shown to terminals 38 and FIG. 3a, typically only one connection would be made for the anode connection of an x-ray tube. A resilient gasket 52 is mounted at shoulder 54 of insulating plug 36. A cable flare fitting 56 retains insulating plug 36 to cable 48 by means of a clamp 58. Collar 60 is free to rotate with respect to plug 36 and has an inner threaded ring 62 which mates with threads 64 in cylinder portions 16a,b when the mating portions of the terminals are joined. Either straight or curved cable strain relief may be provided by fittings 66a or b. Once the cable side or plug assembly is complete, it is typically filled with an electrically insulating compound 67 such as polyurethane.
As can readily be seen, this prior art cable termination system comprises a considerable portion of the total x-ray tube enclosure voume. In addition, it requires a substantial amount of manual assembly of many small parts, thus resulting in a relatively complicated and costly cable termination system. Finally, the complicated nature of the parts and steps of such prior art plug assemblies required their construction to be performed by trained personnel using equipment lending itself only to in-factory use. A consequence of this is that plug assemblies have proven difficult to install in hospitals and other locations of x-ray tube users. For example, the assemblies of FIGS. 3a,b cannot readily be routed through electrical conduit which may be present in x-ray installations. More particularly, the bulky and rigid construction of such prior art plug assemblies prevents "snaking" prior art high voltage cables through curved conduit and has required oversize conduit as well.